Classifier gradients let frozen robot policies adapt to new bodies without demonstrations

Han and Niranjani steer a frozen flow-based VLA with a lightweight embodiment classifier, raising success from 72% to 80% on modified LIBERO controllers.

Top University
Devin Han · Hershraj Niranjani

UC Berkeley

Research Digest··3 min read
The authors train a small classifier to distinguish action chunks that succeed on a source robot from those that succeed on a modified target body, then use its gradient to guide the frozen pi0 policy during sampling.

Han and Niranjani work with pi0, a flow-based vision-language-action policy that generates a 350-dimensional action chunk (50 actions of 7 numbers) from images, state and language instruction through 10 denoising steps.

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